Back to the Basics: What is a Menstrual Cycle

Many of us took a class in grade school, or, at least you will, where we learned the correct anatomical names of our reproductive organs, squirmed in our seats as the teacher held up colorful diagrams of a flaccid penis and tried not to laugh when we were lectured to about the changes that occur during the puberty. Some of us did what we could to score well on the quizzes and tests required to pass the course and never gave our reproductive organs a second thought.

Sadly, outside of school there really aren’t many opportunities to discuss our reproductive bodies. This is mainly because in these awkward health classes we are inadvertently taught to be embarrassed. And that reality, my friends, is harmful to our knowledge, our health, and even our sexual pleasure. So much so that in 2014, the Daily Mail published a story discussing a survey that showed, “half of 26 to 35-year-olds were unable to correctly identify a vagina on a medical diagram of the female reproductive system.” Um, what?

I am convinced that we cannot live healthy lives unless we understand the nuances of our bodies and nothing is more nuanced than the menstrual cycle. According to the Guttmacher Institute, in 2012, just under 10 million women use the Pill as their birth control method of choice, which I fully support. However, I also support knowing how and why our bodies work the way they do. So today, let’s get back to the basics of women’s health and talk about the fantastic menstrual cycle. And I promise, no colorful diagrams.

First thing’s first. The menstrual cycle can last anywhere from *21 to 35 days with the average length being 28 days, with the first day of your period being day one. This monthly cycle is divided into four distinct phases: menstruation, follicular phase, ovulation and the luteal phase.

Phase One: Menstruation

Menstruation occurs when the level of the hormone progesterone dips significantly (progesterone is the hormone responsible for maintaining a pregnancy). For most women, bleeding during menstruation can last anywhere from 2-7 days. Many women experience light brown spotting before their period officially begins, see a gradual increase in flow over the course of a few days which then subsides with some more spotting. Some women start and end bleeding without the warm-up and cool-down which is why they bleed for fewer days (I am not one of those women). During the menstrual cycle, we will shed 2-4 tablespoons of vibrant, nourishing blood.

Phase Two: Follicular

Once menstruation ends, the hormone estradiol begins to stimulate our ovaries. It is in this phase a teeny, tiny follicle develops (sometimes two, or three!) and acts as a “hallway” through which a mature egg will pass. This is called the follicular phase and lasts around a week. Fun Fact: most girls are born with all of the eggs they will ever have, which are millions. So if you think about it, your maternal grandmother actually carried you when she was pregnant with your mom. Fascinating! Anyway, those millions of immature follicles, through puberty and young adulthood, get paired down to around 200-400 eggs. Unlike boys and men who can continue to produce sperm well into late adulthood, a woman has a finite number of eggs.

Phase Three: Ovulation

Phase three is possibly one of the most critical stages: ovulation. Ovulation is when that mature follicle discussed in phase two breaks through the surface of our ovary and is released into our fallopian tube. During this phase, estrogen is produced in the maturing ovary from which some women experience mild side effects: tender breasts or light cramping are common. Light spotting is also possible. This phase typically occurs between days 12 and 18 of the cycle.

At this phase in your cycle, you may notice you become very interested in sex. You may also notice an abundant clear discharge in your underwear or when you use the bathroom. This is completely normal and is your body’s way of telling you you’re fertile. This clear discharge is coming out of your cervix and has a PH balance that is friendly to sperm and actually helps them swim more quickly. At this point in your cycle, you are most fertile. So, if you are not taking hormonal birth control, abstaining from sex during the ovulation phase can help you avoid an unplanned pregnancy from, say, a broken condom. Also during this phase, the uterine wall has begun to thicken in preparation to accept and nourish a fertilized egg. The mature egg only lives for 12-24 hours after it is released from the ovary. If healthy sperm is not there to meet the egg it dissolves and is absorbed into the lining of the uterus.

Phase Four: Luteal Phase

At this point, the leftover follicle in your ovary turns into what is called the corpus luteum and triggers your body to produce progesterone. This is known as the luteal phase. During this phase, progesterone helps sustain the uterine wall and is responsible for all those lovely PMS symptoms we may experience: bloating, tender and swollen breasts, cramping, mood swings, fatigue, headaches, etc. The luteal phase lasts around two weeks during which, the egg floats down to the uterus and, if fertilized, burrows into the uterine wall where the corpus luteum continues to produce progesterone into the 10th week of pregnancy until the placenta can take over. If you do not become pregnant during the luteal phase your progesterone levels will dip. This dip will trigger menstruation and you will find yourself back in phase one.

There you have it, a straightforward chat about what a menstrual cycle is: an incredibly coordinated effort of hormones and communication between body systems. It really is an amazing thing, that menstrual cycle. Whether you are a young girl experiencing her first menstrual cycle or just a woman who wants to feel more connected to her body, our menstrual cycle is truly something we should appreciate.

*Note: This is the most basic explanation of the menstrual cycle, a lot of women and girls experience menstrual irregularities. Some irregularities are normal (like if you just started your period within the last 2 years) and others may be a sign of underlying health issues like Endometriosis or Polycystic Ovarian Syndrome.

amy sutherland - founder

Hey all! My name is Amy Sutherland (she/her), and I have been passionate about sexual health since before I hit puberty. I've spent most of my adult life working as a writer focusing on health and wellness. More particularly, women’s reproductive health.